I've successfully implemented a half-duplex sequencing mechanism, which I've illustrated below. The outdoor components are represented in green. In my current setup, I utilize a PLC to control both an HPA (Kuhne) and an RF Switch (Radiall).
The current configuration functions as intended, but it necessitates separate RF cables for transmitting (Tx) and receiving (Rx). Additionally, the LNA is powered using conventional power cables, rather than being powered through the coaxial cable. I'm seeking to enhance this scheme to utilize just a single RF cable while eliminating the need for separate power cables. I've conceived two potential approaches, although I'm uncertain about their feasibility.
Scheme 1: In this proposal, I plan to incorporate a Bias-T to power the LNA, coupled with Voice-Operated Switch (VOX) capability. The RF switch would still manage HPA PPT (Push-to-Talk) and Tx/Rx selection. Given the LNA's VOX functionality, I'm assuming it will automatically transition to "transmit mode" when it detects a power surge during transmission.
Scheme 2: This arrangement closely resembles the previous scheme, but with a notable distinction: the LNA lacks VOX capability. Instead, the LNA's transition to "transmit mode" relies on powering down the Bias-T. Consequently, the PLC can control the sequencing by toggling the bias-T's power.
I welcome any suggestions for improvements or any identification of errors within the proposed schemes. Your insights would be greatly appreciated.